Abstract: The probability of the prestressed concrete beam bridge is analyzed based on Fault Tree method. The dominant failure modes are identified using the overall critical strength branch-and-bound criterion firstly，and then, the reliability index of these modes is calculated by JC method. Finally, the failure probability of the structural system is calculated with Ditlevsen upper and lower bounds formula. This procedure is illustrated by taking a highway bridge over the Hanjiang River in China as an engineering example. A comparison with the real running state of the bridge shows that the proposed procedure can predict the structural behavior of practical bridges and can be applied to analyzing and evaluating the safety and reliability of the prestressed concrete bridge.